This invention relates to flavor-enhancing smoking filters. More particularly, this invention relates to filters in which flavorants are arrayed in zones over which smoke passes to absorb flavorant, but which zones, themselves, permit the passage of none or a minority of the smoke.
The art is continually searching for means to improve the flavor of smoke produced by a burning tobacco rod. One method to accomplish this is to have the smoke pass through an area having different quality tobacco or tobacco flavorants. The smoke incorporates flavorants, usually through volatilization, and the quality of the smoke's flavor is thereby changed. Several embodiments based on this method have been described.
Haley, U.S. Pat. No. 1,931,131, refers to a method for blending the aroma of cigarettes by connecting two cigarettes of different blends end-to-end. As the smoke of the first cigarette is drawn through the second, it incorporates flavor from the second tobacco. However, because the cigarette is long, as the smoke is drawn through the second tobacco, it may condense. The tobacco, itself, is hygroscopic and contributes to this condensation. The resulting condensation can absorb soluble flavors and remove them from the smoke.
Sway, U.S. Pat. No. 3,913,590, also refers to cigarettes having distinct tobacco sections, this time separated by an inert, porous, non-combustible element. The tobacco at the burnable end of the cigarette contains tobacco from which unwanted substances have been removed. A different kind of tobacco at the mouth end of the cigarette flavors the smoke. This cigarette poses problems of condensation and filtration similar to Haley. Furthermore, the inert element may cool the smoke so that it cannot volatilize the flavorants at the mouth end of the cigarette.
Avedikian, U.S. Pat. No. 3,368,566, refers to a filter cigarette in which the smoke from the burnable charge is extensively filtered to remove a substantial amount of the particulate matter, other combustion products and, consequently, the taste. Since all that remains is a gas stream, there is no tobacco flavor to blend or improve. Instead, Avedikian uses a charge of high quality tobacco at the mouth end of the cigarette to reflavor the gas stream produced by this filtration.
Berger, U.S. Pat. No. 4,291,711 refers to a tobacco smoke filter comprising a fibrous filtering material having a high resistance-to-draw which surrounds a reconstituted tobacco member having low resistance-to-draw. The reconstituted tobacco sheet has flow passages having a high surface area for contact with the smoke passing through. Because the reconstituted tobacco member has a low resistance-to-draw, it permits the passage of a majority of the smoke through it. Consequently, the flavorant may condense the smoke and filter flavors from it.
It is an object of this invention to provide a smoking filter which enhances the flavor of smoke passing through it but which reduces or eliminates filtration of the smoke by the flavorant.